1. Field of the Invention
This invention relates generally to apparatus used in conjunction with a respiratory support system. More specifically, the present invention relates to a method and apparatus for using a suction catheter device as part of a respiratory support system such as described in copending patent applications, Ser. No. 07/962,756 filed Oct. 19, 1992 for "Respiratory Support System and Suction Catheter Device Therefor" Ser. No. 07/962,757 filed Oct. 19, 1992 for "Suction Control Valve" and Ser. No. 07/962,755 filed Oct. 19, 1992 for "Ventilator Manifold with Accessory Access Port". Even more specifically, the present invention relates to the use of a suction catheter device which includes a sputum trap attachment for collecting and transporting a sample of sputum from a patient for later analysis.
2. Prior Art
Respiratory support systems used for the ventilation of critically ill patients are now commonly used in medical facilities. Typically, a prior art respiratory support system includes a tracheal tube positioned either directly, or through the nose or mouth, into the trachea of a patient, a manifold connected to the tracheal tube at one port position thereof, and a source of breathable gas connected at a second port thereof. The purpose of the respiratory support system is to assist the patient in maintaining adequate blood oxygenation levels without overtaxing the patient's heart and lungs.
While a patient is attached to the respiratory support system, it is periodically necessary to aspirate fluid from the patient's trachea or lungs. In the past, in order to accomplish aspiration, it has been necessary to disassemble part of the respiratory support system, either by removing the ventilator manifold therefrom or by opening a port of the manifold and inserting a small diameter suction tube down the tracheal tube and into the patient's trachea and lungs. The fluid was then suctioned from the patient and the suction catheter was removed and the respiratory support system reassembled. However, due to the interruption of respiratory support during this procedure, a patient's blood oxygen often dropped to an unacceptably low level, even when other previously known breathing assistance efforts were simultaneously provided. Further, there has been no solutions offered to the problem of sputum sample collection during aspiration, which also avoids the problem of respiratory support interruption.
U.S. Pat. No. 5,073,164 to Hollister et al. is generally exemplary of the prior art of suction catheter devices. Hollister et al. includes a ventilator manifold having an access port therethrough which is adapted to receive a connector of a suction catheter device. The suction catheter device positions a catheter within the ventilator manifold without substantial manifold pressure loss. The suction catheter device includes an envelope which is positioned around the catheter portion thereof in order to prevent contamination of the catheter surface intended to be inserted into the patient's trachea and lungs.
Although this type of ventilator manifold and suction catheter device connection allows continuous respiratory support of the patient during suctioning of fluid from the patient's trachea and lungs, it nevertheless has several drawbacks associated with its use. For example, removal of the suction catheter device from the manifold, such as for the purpose of replacing the suction catheter device, or separation of the suction catheter from the suction control valve such as for the purpose of attaching a sputum trap for collecting a sputum sample from the patient cannot be accomplished without losing internal manifold pressure and compromising the integrity of the respiratory system. Since separation of the Hollister et al. suction catheter device from its suction control valve cannot be accomplished without opening the manifold to atmospheric pressure through the catheter, use of the Hollister et al. device for purposes of collecting a sputum sample from the suction catheter thereof is not possible. Instead, a separate collection device is required.
A sputum collection device of this nature which is generally exemplary of the prior art is U.S. Pat. No. 4,273,126 to Grane et al. Grane et al. includes a hand held container attached to a suction catheter at an inlet thereof and a suction source at an outlet thereof. The suction catheter is inserted into the patient's trachea and lungs and sputum is aspirated into the container. The suction catheter is then withdrawn and the sputum sample is analyzed.
As is clearly obvious, no means exist on the Grane et al. device to allow its use with a ventilator manifold in such a manner as to avoid PEEP pressure losses during sputum collection.
There therefore exists a need in the art for a respiratory support system which includes a ventilator manifold which allows simple attachment and detachment of a suction catheter device therefrom during continuous patient respiratory support, without substantial pressure loss from the manifold and without substantial collection of body fluids in the manifold. There also exists a need in the art for a sputum collection device such as a sputum trap which can be attached to, and detached from, the suction catheter device for collection of a sputum sample without causing interior pressure loss from the ventilator manifold.